In a connector system it must be ensured that each plug and counter plug are correctly assigned to each other. To achieve a correct assignment it is known from German Patent 2 248 268 A1 to provide multiple grooves on the housing of the socket part and a protrusion on the corresponding plug part which permits insertion of the plug part only into the corresponding socket part. For this purpose, specially configured connector housings have to be used which permit coding of the plug and counter plug.